The role of transcription and messenger RNA stability in the regulation of epidermal growth factor receptor gene expression in regenerating mouse liver.

The influence of partial hepatectomy on epidermal growth factor receptor gene expression was studied in mouse liver. Epidermal growth factor receptor binding and epidermal growth factor receptor messenger RNA levels in the liver showed a rapid peak 8 hr after partial hepatectomy, whereas the sham operation had no effects on these levels. The peak epidermal growth factor receptor messenger RNA level was approximately threefold higher than preoperative values. The increase in epidermal growth factor receptor messenger RNA levels occurred primarily as a consequence of an increase in the rate of transcription. Partial hepatectomy slightly increased the half-life of epidermal growth factor receptor messenger RNA in the liver from 2.8 to 3.6 hr. Treatment of partially hepatectomized mice with cycloheximide increased hepatic epidermal growth factor receptor messenger RNA levels about fivefold by prolonging the half-life of the messenger RNA to 11.2 hr, although this treatment inhibited the increase in transcription induced by partial hepatectomy. Cycloheximide also increased epidermal growth factor receptor messenger RNA levels in the liver or kidney of sham-operated mice about threefold, primarily through stabilizing epidermal growth factor receptor messenger RNA. In contrast, cycloheximide had no effects on beta-actin messenger RNA levels in the liver and kidney. These results suggest that transcription induced by partial hepatectomy requires protein synthesis and that labile proteins are involved in the regulation of the stability of epidermal growth factor receptor messenger RNA.